Current industrial automotive trends to reduce the number of overall mechanical components of the vehicle and to reduce the overall vehicle weight have contributed to the development of system-by-wire applications, which are typically referred to as X-by-wire systems. One such X-by-wire system that has received increased attention is a brake-by-wire (BBW) system, sometimes referred to as an electronic braking system (EBS).
Unlike conventional mechanical braking systems, BBW systems actuate one or more vehicle braking components via an electronic signal that is generated by an on-board processor/controller. In some systems, a BBW system is implemented by supplanting a conventional hydraulic fluid-based service braking system with an electrical-based system to perform basic braking functions. The electrical-based systems implemented in a conventional BBW system include brake assemblies with an electronic brake actuator such as, for example, an electronically-controlled brake caliper typically referred to as an “e-caliper”. Conventional e-calipers exclude any control logic, and merely operate in response to current generated by a single power source located externally from the brake assembly and at a remote area of the vehicle.
Since BBW systems typically remove any direct mechanical linkages and/or hydraulic force-transmitting-paths between the vehicle operator and the brake control units, much attention has been given to designing BBW control systems and control architectures that ensure reliable and robust operation. Various design techniques have been implemented to promote the reliability of the BBW system including, for example, redundancy, fault tolerance to undesired events (e.g., events affecting control signals, data, hardware, software or other elements of such systems), fault monitoring, and recovery.